From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lamorak.hansenpartnership.com (lamorak.hansenpartnership.com [198.37.111.173]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7FE4A2475CD; Mon, 20 Oct 2025 23:13:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.37.111.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761002004; cv=none; b=ExLnEhH33L1J3PiXup69nzI54sOMFY9zL+Baf1rxD545/6xbqU2gS2sYv7PhQrewHp9cgwlhPMo8xXdPip24Jc40vWDZgxCj9eb9di1UTlmMoy8+WYnNt8iEaf84GVHmGUWyAcXl3rlo+1q8sfaQTe6oTktjQqyT0Fsit245ZyU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761002004; c=relaxed/simple; bh=d1CzqJujTpmoonXQjO/rxn6MhmNh0S7D56wVmjAHJRc=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=q0ymSGk0oCYl2i62lR3iccpqAoGX81SEs32hoagvOO4QOUXrQGfy/5mOH+iOYnOPBu3wLMTtsncW9s/3Q1cHRzhPrk3WAw7h51WOYWZA8++XMeFKCqPeeZwShZObVk7P5sivx3hTtInvfTXMuVEHDcAtFlGFyShJidNsUBMf97s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=HansenPartnership.com; spf=pass smtp.mailfrom=HansenPartnership.com; dkim=pass (1024-bit key) header.d=hansenpartnership.com header.i=@hansenpartnership.com header.b=HEwesnfC; arc=none smtp.client-ip=198.37.111.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=HansenPartnership.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=HansenPartnership.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=hansenpartnership.com header.i=@hansenpartnership.com header.b="HEwesnfC" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=hansenpartnership.com; s=20151216; t=1761002000; bh=d1CzqJujTpmoonXQjO/rxn6MhmNh0S7D56wVmjAHJRc=; h=Message-ID:Subject:From:To:Date:In-Reply-To:References:From; b=HEwesnfChn6fQJ7tdcLNShiozcyG9DNdW5U9kYnizTGLr0ov2XVFC33PuK2qFBa5s iHal9wxBagsGA+T8EP9/NTCO5JcJv4iCLo0TT0Ln97pgKg5JfM6CUny7qUJZxpFsfQ He994C96cGXGlnEJ9v10GAz0gugocJhDaBw52qzg= Received: from [172.20.40.240] (unknown [32.142.2.106]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lamorak.hansenpartnership.com (Postfix) with ESMTPSA id 530AB1C027F; Mon, 20 Oct 2025 19:13:20 -0400 (EDT) Message-ID: Subject: Re: [PATCH bpf-next v2 0/3] BPF signature hash chains From: James Bottomley To: Alexei Starovoitov , Paul Moore Cc: Linus Torvalds , Alexei Starovoitov , KP Singh , Blaise Boscaccy , bpf , LSM List , "K. Y. Srinivasan" , Daniel Borkmann , Andrii Nakryiko , wufan@linux.microsoft.com, Quentin Monnet Date: Mon, 20 Oct 2025 19:13:19 -0400 In-Reply-To: References: <20250929213520.1821223-1-bboscaccy@linux.microsoft.com> <88703f00d5b7a779728451008626efa45e42db3d.camel@HansenPartnership.com> <42bc677e031ed3df4f379cd3d6c9b3e1e8fadd87.camel@HansenPartnership.com> Autocrypt: addr=James.Bottomley@HansenPartnership.com; prefer-encrypt=mutual; keydata=mQENBE58FlABCADPM714lRLxGmba4JFjkocqpj1/6/Cx+IXezcS22azZetzCXDpm2MfNElecY3qkFjfnoffQiw5rrOO0/oRSATOh8+2fmJ6el7naRbDuh+i8lVESfdlkoqX57H5R8h/UTIp6gn1mpNlxjQv6QSZbl551zQ1nmkSVRbA5TbEp4br5GZeJ58esmYDCBwxuFTsSsdzbOBNthLcudWpJZHURfMc0ew24By1nldL9F37AktNcCipKpC2U0NtGlJjYPNSVXrCd1izxKmO7te7BLP+7B4DNj1VRnaf8X9+VIApCi/l4Kdx+ZR3aLTqSuNsIMmXUJ3T8JRl+ag7kby/KBp+0OpotABEBAAG0N0phbWVzIEJvdHRvbWxleSA8SmFtZXMuQm90dG9tbGV5QEhhbnNlblBhcnRuZXJzaGlwLmNvbT6JAVgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQWAgMBAh4BAheAAhkBFiEE1WBuc8i0YnG+rZrfgUrkfCFIVNYFAmBLmY0FCRs1hL0ACgkQgUrkfCFIVNaEiQgAg18F4G7PGWQ68xqnIrccke7Reh5thjUz6kQIii6Dh64BDW6/UvXn20UxK2uSs/0TBLO81k1mV4c6rNE+H8b7IEjieGR9frBsp/+Q01JpToJfzzMUY7ZTDV1IXQZ+AY9L7vRzyimnJHx0Ba4JTlAyHB+Ly5i4Ab2+uZcnNfBXquWrG3oPWz+qPK88LJLya5Jxse1m1QT6R/isDuPivBzntLOooxPk+Cwf5sFAAJND+idTAzWzslexr9j7rtQ1UW6FjO4CvK9yVNz7dgG6FvEZl6J/HOr1rivtGgpCZTBzKNF8jg034n49zGfKkkzWLuXbPUOp3/oGfsKv8pnEu1c2GbQpSmFtZXMgQm90dG9tbGV5IDxqZWpiQGxpbnV4LnZuZXQuaWJtLmNvbT6JAVYEEwEIAEACGwMHCwkIBwMCAQYVC 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 8mT2Eh9SkH+YVOmaKsajgZgrBxA7fWmGoxXswEVxJIFj3vW7yNc0C5HaUdYa5iGOMs4kg2ht4s7yy7NRQuh7BifWjo6BQ6k4S1H+6axZucxhSV1L6zN9d+lr3Xo/vy1unzA== Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.50.3 Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Fri, 2025-10-17 at 11:03 -0700, Alexei Starovoitov wrote: > On Thu, Oct 16, 2025 at 6:36=E2=80=AFPM Paul Moore > wrote: > >=20 > > On Thu, Oct 16, 2025 at 6:01=E2=80=AFPM Alexei Starovoitov > > wrote: > > > On Thu, Oct 16, 2025 at 1:51=E2=80=AFPM Paul Moore > > > wrote: > > > > On Sun, Oct 12, 2025 at 10:12=E2=80=AFPM Paul Moore > > > > wrote: > > > > > On Sat, Oct 11, 2025 at 1:09=E2=80=AFPM James Bottomley > > > > > wrote: > > > > > > On Sat, 2025-10-11 at 09:31 -0700, Alexei Starovoitov > > > > > > wrote: > > > > > > > On Sat, Oct 11, 2025 at 7:52=E2=80=AFAM James Bottomley > > > > > > > wrote: > > > > > > > >=20 > > > > > > > > It doesn't need to, once we check both the loader and > > > > > > > > the map, the integrity is verified and the loader can > > > > > > > > be trusted to run and relocate the map into the bpf > > > > > > > > program > > > > > > >=20 > > > > > > > You should read KP's cover letter again and then research > > > > > > > trusted hash chains. Here is a quote from the first > > > > > > > googled link: > > > > > > >=20 > > > > > > > "A trusted hash chain is a cryptographic process used to > > > > > > > verify the integrity and authenticity of data by creating > > > > > > > a sequence of hash values, where each hash is linked to > > > > > > > the next". > > > > > > >=20 > > > > > > > In addition KP's algorithm was vetted by various security > > > > > > > teams. There is nothing novel here. It's a classic > > > > > > > algorithm used to verify integrity and that's what was > > > > > > > implemented. > > > > > >=20 > > > > > > Both KP and Blaise's patch sets are implementations of > > > > > > trusted hash chains.=C2=A0 The security argument isn't about > > > > > > whether the hash chain algorithm works, it's about where, > > > > > > in relation to the LSM hook, the hash chain verification > > > > > > completes. > > >=20 > > > Not true. Blaise's patch is a trusted hash chain denial. > >=20 > > It would be helpful if you could clarify what you mean by "trusted > > hash chain denial" and how that differs from a "trusted hash > > chain". >=20 > Paul, > This is getting ridiculous. You're arguing about the code that you > don't understand. Stop this broken phone and let Blaise defend his > code. That might be my fault: I told Blaise only to respond to technical issues and arguing about what you want to name an algorithm isn't really a technical=C2=A0issue with the patch. The point, for me, is when doing integrity tests both patch sets produce identical results and correctly detect when integrity of a light skeleton is compromised (in mathematical terms that means they're functionally equivalent).=C2=A0 The only difference is that with Blaise's patch set verification completes before the LSM load hook is called and with KP's it completes after ... and the security problem with the latter case is that there's no LSM hook to collect the verification result. Regards, James